Manufacturing Costs: What to Calculate, Where Mistakes Happen, and How to Get Things in Order

A dangerous illusion

Manufacturing has its own particular illusion of control. The warehouse is in order. The figures in 1C or a spreadsheet add up. The accountant says, “The month is closed.” The production engineer shows you a cost calculation. And it looks as though the system is working.

But ask just one uncomfortable question:

• If raw material prices rise by 8% tomorrow, exactly which products will become unprofitable?
• If a customer asks for a 5% discount, can we actually afford to give it?
• If we remove one production stage, how much will we save, and will quality suffer?

Suddenly, there is no answer. Only assumptions.

Product cost often exists as a figure “for the accounts”, rather than a tool for making decisions. It is calculated to close the month. What it should do is show where the business makes money and where it simply moves money around.

Until costs are broken down by process, batch, and variance, production can look stable without being predictable.

Let us look at what you actually need to track in a cost calculation, where distortions arise, and how to make the figures accurate enough to support decisions rather than merely record what has happened.

What you actually need to calculate in manufacturing

When someone says, “We have calculated the cost,” they usually mean a single figure. But in manufacturing, one figure is often not enough. There are at least three levels of calculation, each answering different questions.

The first level is the direct cost of a specific batch. These are costs that can be directly linked to making it: raw materials, supplies, components, the wages of the people who worked on that batch, the related employer payroll contributions, and sometimes energy, where it can reasonably be attributed to the output. Process losses also need to be visible separately.

The key words are “a specific batch”. Not one average figure for every order. Not an abstract “overall product cost”.

If raw materials were purchased at different prices, if consumption differed from the standard, if one batch required three shifts while another was produced at a normal pace, the costs can differ too. Those differences show where profit is made and where hidden losses occur.

The second level is manufacturing cost, including allocated production overheads. This introduces costs you cannot physically touch in the finished product, but without which production cannot operate: equipment depreciation, supervisors’ and shift managers’ salaries, rent or upkeep of production premises, servicing, and maintenance. These costs are allocated according to established rules, rather than simply adding every business expense to the cost of output.

Looking only at direct costs creates a dangerous illusion of a high margin. A product appears to make good money, while in reality it does not cover the infrastructure needed to manufacture it.

Then there is the third level: the complete cost picture for an order. This is where accuracy is easily lost.

Production costs are joined by everything that happens around the product: delivery to the customer, finished goods storage, packaging for shipment, costs caused by returns, and a share of the company’s indirect expenses. Losses from defective production must also be visible. But each amount is counted only once: anything already included in an earlier calculation must not be added again. The figure then changes — sometimes by tens of percentage points rather than just a few.

Only at this stage can you see how much an order leaves after all the costs included in the calculation. Not the attractive number on a costing sheet, but what the business has earned after the product has completed its journey from raw material purchasing to customer shipment.

This is a management view of an order’s result. It does not mean that every expense listed should be included in manufacturing cost for financial accounting. And when comparing margins across orders, you need to use the same scope of costs.

Here is a question worth asking yourself honestly: can you see these three levels separately for every order? Or do you have just one average figure that reassures you without explaining anything?

Where mistakes happen most often

Costing mistakes rarely look like arithmetic errors. The formulas are correct, the spreadsheets are complete, and the report is tidy. At first glance, everything makes sense. But the problem lies in the logic of the calculation, not the maths.

The first common trap is using one monthly average cost for different orders. All costs are divided by total output to produce an “objective” figure. But that apparent stability hides very different realities: batches were made at different times, raw materials were purchased at different prices, there was excess consumption, there were stoppages, and some products remained unfinished.

One order may have made a loss, another may have covered it, and the average figure still showed an acceptable result.

Weighted average cost is not inherently wrong as an inventory valuation method. The problem arises when averaging replaces an analysis of the costs and results of individual orders.

The second mistake is invisible work in progress. If WIP is not valued correctly, it becomes difficult to explain why there is plenty of work but not enough liquidity: some resources have already been invested in partly finished goods that have not yet generated revenue.

The third risk area is defective production. If losses are spread across a single total without detail, there is no way to identify exactly where the problem occurs, and it happens again.

The fourth mistake is allocating labour costs without a sound link to a specific batch. Profitability figures become distorted and fail to reflect the actual workload.

Finally, there is confusion between VAT and cash flow. Output VAT is not business revenue. And profit is not the same as money in the bank: a sale can be profitable even though the customer has not yet paid.

An example

Consider an illustrative example showing how all these mistakes can combine into one distorted picture.

Imagine a manufacturer of made-to-order cabinet furniture. It produces 40 sets in a month. The costs attributed to those sets for management analysis total UAH 2,095,000. The report uses a simple calculation: 2,095,000 / 40 = UAH 52,375 per set. The average looks stable.

But break the figures down by batch, and the picture changes.

The first batch of 10 sets was made at the start of the month using existing chipboard stock costing UAH 820 per sheet. The second batch of 15 sets used a new purchase costing UAH 910 per sheet. The third batch of 15 sets was affected by a two-day equipment stoppage, increasing the time required and resulting in some defective production. In this example, material costs are assigned to each batch using the cost of the specific inventory consumed.

The average of UAH 52,375 concealed the difference in costs per set:

• First batch: UAH 46,000.
• Second batch: UAH 52,000.
• Third batch: UAH 57,000 because of excess consumption, defect losses, and additional labour costs.

Total: 10 × 46,000 + 15 × 52,000 + 15 × 57,000 = UAH 2,095,000.

Each set in the third batch therefore cost UAH 11,000 more than a set in the first. Yet the overall average does not reveal this. To determine each batch’s margin, its costs must be compared with its actual selling price excluding VAT.

Now add the second mistake: work in progress. Alongside the 40 completed sets, another 8 remain on the shop floor at different stages of completion at month-end, with UAH 380,000 in materials and labour invested in them. This amount is separate from the UAH 2,095,000 attributed to the finished sets. WIP is not shown separately in financial planning. The owner sees little money left in the bank and concludes that it was “a weak month”, while a substantial share of resources is still tied up in production.

The third issue is defective production. An incorrectly adjusted milling machine spoiled UAH 120,000 worth of material. In this example, those losses are already included in the third batch’s total cost of UAH 855,000 and must not be added again. But the summary report does not show them separately. Nobody can see that a particular production area created additional costs for this batch.

Here, we are examining costs and losses for management analysis. Attributing them to a batch for this purpose does not mean that every defect or downtime cost can be included in the carrying amount of finished goods.

The fourth problem is labour cost. Employees worked on two large orders at the same time. Their pay was allocated in proportion to the number of items produced rather than the time actually spent. As a result, costs were understated for the complex order with non-standard fittings and overstated for the standard order. The report misrepresents the profitability of both.

Finally, VAT. The manufacturer sold these 40 sets for UAH 3,000,000 including VAT at 20%. Of that amount, UAH 500,000 is VAT, and revenue excluding VAT is UAH 2,500,000. However, UAH 500,000 is not automatically the amount payable to the state: the payable amount is determined through the VAT return, taking input VAT credit and other relevant figures into account. Some customers have not yet paid, so cash receipts need to be analysed separately from the result of the sales.

Look at the example as a whole, and the pattern becomes clear. No single mistake appears critical. Together, however, they create an illusion of control: averages hide differences between batches, while profit on paper is confused with money in the bank.

This is why costs need to be visible for specific batches, rather than just “on average for the month”, with variances, work in progress, defects, and actual workload taken into account. Cash flow needs its own separate oversight.

A practical approach: getting things in order

You cannot put costing in order with a single formula. You need to change how manufacturing costs are recorded and make the approach consistent.

It starts with batch tracking. Every batch needs its own history: which materials were used, in what quantities, how consumption differed from the standard, and what was actually produced. This is how excess consumption becomes visible, along with the point at which a process starts losing efficiency.

Next come standard and actual costs. Standard costing shows what should happen. Actual costing shows what really happened. If the cost is higher, you need to understand why: a change in material prices, additional working time, downtime, or process losses.

Work in progress is a separate area. These are resources still in production. It is important to see their value and how long they remain in the production cycle.

You also need to separate the result of production from the costs of running the company to understand where the financial result comes from.

As the item range grows, batches multiply, and raw material prices change regularly, maintaining accuracy in manual records becomes increasingly difficult. You need a system that can calculate costs by batch, track WIP, record variances, and produce reports that support decisions.

This is where Skynum can help. The system takes into account how manufacturing businesses operate in Ukraine: batch tracking, material movements, cost calculations, work-in-progress control, the separation of cost categories, and keeping VAT separate from the financial result.

When record-keeping becomes systematic, product cost stops being a rough estimate and becomes a reliable basis for decisions — from pricing to planning production capacity.

Conclusions

When costs are calculated correctly, they stop being just a reporting figure and become a tool for action. You can identify an unprofitable order in time, review prices, adjust material consumption standards, optimise inventory, or decide whether to scale.

Even when demand exists, a manufacturing business can lose profit because its costs are unclear. Accurate costing makes it easier to see where the business earns money and where it loses it.

That gives you confidence in the figures and lets you plan growth with a clear understanding of where the business is heading and how it makes money.